People who ate rice had arsenic levels that were 44 percent greater than those who had not, according to the Consumer Reports analysis of federal health data. Arsenic can occur naturally in nature, but inorganic arsenic is considered a carcinogen, and the chemical has been shown to cause a variety of cancers in humans.

The study found that white rice grown in the states of Arkansas, Louisiana, Missouri and Texas generally had higher levels of total arsenic and inorganic arsenic in tests than samples from other states. The study says this may be due to the fact that the region has a long history of producing cotton, which was heavily treated with arsenical pesticides for decades.

Experts also found that the average total and inorganic levels of the chemical were always higher for brown rice than for white, possibly because arsenic levels concentrates in the outer layers of a grain. White rice is polished to reduce those surface layers.

The high levels of arsenic detected in infant cereals was especially concerning, according to Consumer Reports, because it is generally recommended as a baby’s first solid food. Consumer Reports recommends that babies eat no more than 1 serving of infant rice cereal a day.